/Engine/Plugins/Online/OnlineFramework/Source/Party/Public/Chat/ChatSlashCommands.h
struct FAutoCompleteStruct
FString
FullString
Cacheing data with strings is tricky because they will become invalid when the user changes their localization but a user can't change this while typing a command, so it is okay in this case.
TWeakObjectPtr<...
OptionalTargetUser
TWeakPtr< const...
SlashCommand
TArray<FString...
Tokens